Intel's Barrett hints at 64-bit compatibility glitches

Xeon contains magic Intel-only instructions

IDF At long last, Intel has done the deed and followed AMD with 64-bit extensions to its 32-bit processors. But how compatible will Intel's 64-bit Xeon be with AMD's Opteron?

CEO Craig Barrett said that Intel plans to introduce the 64-bit extensions in the Xeon processor line (Nacona) in the second quarter. The Prescott chip will arrive at "roughly the same time" with the 64-bit extensions and be aimed at single processor servers and workstations. In 2005, the extensions will arrive for large, multiprocessor servers.

Intel won't say if it has licensed AMD's x86-64 extensions. But Barrett seemed to hint that Intel's technology will be somewhat less than completely compatible with AMD's instruction set.

"For the most part, (software) will run on both systems," he said. "Intel has some (things) unique to Intel, which we will make sure people write, port and tune to."

Reports suggest that Microsoft, which is committed to producing a 64-bit version of Windows for the Itanium processor, balked at supporting two more 64-bit versions, for AMD's x86-64 and Intel's Yamhill. (Microsoft once supported Windows NT ports for a number of processors including MIPS, Alpha and PowerPC). AMD founder Jerry Sanders extracted a commitment from Bill Gates to port Windows to x86-64, although we're still waiting for this to appear.

Sources say the Intel and AMD technology is very similar and that software should run well on both systems. How well? Barrett has left us just enough room for doubt. ®